Electrical Wiring: Definitions

Wiring Methods

• Accessible: Wiring methods that can be removed or exposed without damaging the building structure or finish.
• Inaccessible: Permanently closed in by the building structure or finish.

Equipment Accessibility

• Accessible: Equipment that allows close approach, not guarded by locked doors or elevation.
• Readily Accessible: Equipment that can be reached quickly for operation, renewal, or inspection without obstacles or portable ladders.

Electrical Properties

• Ampacity: The maximum current a conductor can carry continuously without exceeding its temperature rating under specific conditions.
• Bonded (Bonding): Connected to establish electrical continuity and conductivity.

Bonding Components

• Bonding Conductor/Jumper: A reliable conductor for ensuring electrical conductivity between metal parts that must be connected.
• Equipment Bonding Jumper: Connects two or more parts of the equipment grounding conductor.
• Main Bonding Jumper: Connects the grounded circuit conductor and the equipment grounding conductor at the service.
• System Bonding Jumper: Connects the grounded circuit conductor and the equipment grounding conductor at a separately derived system.

Branch Circuits

• Branch Circuit: The conductors between the final overcurrent device and the outlet(s).
• Individual Branch Circuit: Supplies only one utilization equipment.
• Appliance Branch Circuit: Supplies outlets for appliances and has no permanently connected luminaires that are not part of an appliance.
• General-Purpose Branch Circuit: Supplies two or more receptacles or outlets for lighting and appliances.
• Multiwire Branch Circuit: Includes two or more ungrounded conductors with a voltage between them, and a grounded conductor with equal voltage between it and each ungrounded conductor.

Circuit Breakers

• Circuit Breaker: A device that opens and closes a circuit by nonautomatic means and automatically opens the circuit on overcurrent without damage.
• Adjustable: Can be set to trip at various current and/or time values within a range.
• Instantaneous Trip: No intentional delay in tripping action.
• Inverse Time: Introduces a delay in tripping action that decreases as current magnitude increases.
• Nonadjustable: Cannot be adjusted to alter the tripping current or time.
• Setting: The current or time value at which an adjustable circuit breaker is set to trip.

Concealment and Conductors

• Concealed: Rendered inaccessible by the building's structure or finish.
• Bare Conductor: A conductor with no covering or electrical insulation.
• Covered Conductor: A conductor encased in material not recognized as electrical insulation.
• Insulated Conductor: A conductor encased in material recognized as electrical insulation.

Conduit Systems

• Conduit Body: A separate part of a conduit or tubing system that allows access via a removable cover at junctions or terminal points.
• Boxes like FS and FD are not conduit bodies.

Electrical Loads and Control

• Continuous Load: A load where the maximum current is expected to continue for 3 hours or more.
• Controller: A device or group of devices that governs the electric power delivered to connected apparatus.
• Selective Coordination: Localization of an overcurrent condition using overcurrent protective devices and their settings for the full range of fault current and opening times.
• Copper-Clad Aluminum Conductors: Conductors made from copper-clad aluminum with the copper metallurgically bonded, forming at least 10% of the cross-sectional area.

System Safety and Design

• Dead Front: Equipment without live parts exposed on the operating side.
• Demand Factor: The ratio of maximum demand to total connected load.
• Device: A unit that carries or controls but does not utilize electrical energy.
• Disconnecting Means: A device by which circuit conductors can be disconnected from their source.
• Dusttight: Constructed to prevent dust from entering under specified test conditions.

Duty Types

• Continuous Duty: Operation at a constant load for a long time.
• Intermittent Duty: Alternate intervals of load and no load, load and rest, or load, no load, and rest.
• Periodic Duty: Intermittent operation with regularly recurrent load conditions.
• Short-Time Duty: Operation at a constant load for a short, specified time.
• Varying Duty: Operation at loads and intervals subject to wide variation.

Dwelling Definitions

• Dwelling Unit: A single unit providing complete and independent living facilities.
• One-Family Dwelling: A building with only one dwelling unit.
• Two-Family Dwelling: A building with two dwelling units.
• Multifamily Dwelling: A building with three or more dwelling units.

Grounding and Protection

• Effective Ground-Fault Current Path: A low-impedance path to carry current under ground-fault conditions, facilitating overcurrent device operation.
• Enclosed: Surrounded by a case, housing, or wall to prevent accidental contact with energized parts.
• Enclosure: The case or housing to prevent contact with energized parts or protect equipment from damage.

General Terms

• Equipment: Includes materials, fittings, devices, appliances, and luminaires used in an electrical installation.
• Exposed (Live Parts): Capable of being inadvertently touched due to lack of guarding, isolation, or insulation.
• Exposed (Wiring Methods): On or attached to the surface or behind accessible panels.
• Externally Operable: Operated without exposing the operator to live parts.

Feeder and Lighting

• Feeder: Conductors between the service equipment or power supply source and the final branch-circuit overcurrent device.
• Festoon Lighting: A string of outdoor lights suspended between two points.

Components and Grounding

• Fitting: An accessory that performs a mechanical function.
• Ground: The earth.
• Grounded (Grounding): Connected to earth or a conducting body serving in place of the earth.
• Grounded Conductor: A system or circuit conductor intentionally grounded.
• Grounded, Solidly: Connected to ground without any impedance device.
• Ground-Fault Circuit Interrupter (GFCI): A device that de-energizes a circuit when current to ground exceeds established values (4-6 mA for Class A).
• Grounding Conductor, Equipment (EGC): The conductive path that connects non-current-carrying metal parts to the grounded conductor or grounding electrode.

Grounding Elements

• Grounding Electrode: A device that establishes an electrical connection to the earth.
• Grounding Electrode Conductor: Connects the grounding electrode to the equipment grounding conductor or grounded conductor.
• Guarded: Protected by covers, shields, fences, or other means to prevent approach or contact with danger.

Accommodation Definitions

• Guest Room: An accommodation with living, sleeping, sanitary, and storage facilities.
• Guest Suite: Accommodation with two or more rooms providing living, sleeping, sanitary, and storage facilities.

Additional Terms

• Handhole Enclosure: An enclosure for underground systems sized for personnel to reach into for installing/maintaining equipment or wiring.
• Hoistway: A vertical opening in which an elevator or dumbwaiter operates.
• Identified: Recognizable as suitable for a specific purpose or environment.
• In Sight From (Within Sight From, Within Sight): Visible and not more than 15 m distant from another equipment.
• Interrupting Rating: The highest current at rated voltage a device is intended to interrupt.
• Isolated: Not readily accessible without special means.
• Labeled: Equipment with a label indicating compliance with standards, maintained through periodic inspection.
• Lighting Outlet: An outlet for direct connection of a lampholder, luminaire, or pendant cord.
• Listed: Equipment included in a list by an authority indicating it meets standards or is suitable for a specified purpose.
• Live Parts: Energized conductive components.

Location Types

• Location, Damp: Protected from weather but subject to moderate moisture.
• Location, Dry: Not normally subject to dampness or wetness.
• Location, Wet: Subject to saturation with water, such as underground or unprotected outdoor locations.

Lighting and Control Assemblies

• Luminaire: A complete lighting unit including lamp(s) and parts to distribute light and connect to the power supply.
• Motor Control Center: An assembly of enclosed sections with a common power bus containing motor control units.
• Multioutlet Assembly: A raceway designed to hold conductors and receptacles.

Operational Characteristics

• Nonautomatic: Requires human intervention to perform a function.
• Nonlinear Load: A load where the current waveform does not follow the voltage waveform.

System Components

• Outlet: A point on the wiring system where current is taken to supply utilization equipment.
• Overcurrent: Any current exceeding the rated current or ampacity, resulting from overload, short circuit, or ground fault.
• Overload: Operation exceeding normal full-load rating or ampacity that can cause damage or overheating.
• Panelboard: A single panel or group of panel units with buses and overcurrent devices, in a cabinet accessible from the front.
• Plenum: A compartment connected to air ducts forming part of the air distribution system.

Protection and Enclosures

• Raceway: An enclosed channel for holding wires, cables, or busbars.
• Rainproof: Constructed to prevent rain from interfering with operation under specified test conditions.
• Raintight: Constructed to prevent water entrance during exposure to beating rain under specified test conditions.

Receptacles and Services

• Receptacle: A contact device installed at the outlet for connecting an attachment plug or electrical equipment.
• Receptacle Outlet: An outlet where one or more receptacles are installed.
• Service: The conductors and equipment for delivering electric energy from the utility to the premises.
• Service Cable: Service conductors made up in cable form.
• Service Conductors: Conductors from the service point to the service disconnecting means.
• Service Drop: Overhead conductors between the utility and the service point.
• Service-Entrance Conductors, Overhead System: Service conductors between the service equipment and the service drop or overhead conductors.
• Service-Entrance Conductors, Underground System: Service conductors between service equipment and the service lateral.
• Service Equipment: Equipment connected to the load end of service conductors, intended as the main control and cutoff.
• Service Lateral: Underground service conductors between the utility and the service point.
• Service Point: The connection point between the utility and the premises wiring.